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SpectraTr:A novel deep learning model for qualitative analysis of drug spectroscopy based on transformer structure
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作者 Pengyou Fu Yue Wen +4 位作者 Yuke Zhang Lingqiao Li Yanchun Feng Lihui Yin Huihua Yang 《Journal of Innovative Optical Health Sciences》 SCIE EI CAS 2022年第3期107-117,共11页
The drug supervision methods based on near-infrared spectroscopy analysis are heavily dependent on the chemometrics model which characterizes the relationship between spectral data and drug categories.The preliminary ... The drug supervision methods based on near-infrared spectroscopy analysis are heavily dependent on the chemometrics model which characterizes the relationship between spectral data and drug categories.The preliminary application of convolution neural network in spectral analysis demonstrates excellent end-to-end prediction ability,but it is sensitive to the hyper-parameters of the network.The transformer is a deep-learning model based on self-attention mechanism that compares convolutional neural networks(CNNs)in predictive performance and has an easy-todesign model structure.Hence,a novel calibration model named SpectraTr,based on the transformer structure,is proposed and used for the qualitative analysis of drug spectrum.The experimental results of seven classes of drug and 18 classes of drug show that the proposed SpectraTr model can automatically extract features from a huge number of spectra,is not dependent on pre-processing algorithms,and is insensitive to model hyperparameters.When the ratio of the training set to test set is 8:2,the prediction accuracy of the SpectraTr model reaches 100%and 99.52%,respectively,which outperforms PLS DA,SVM,SAE,and CNN.The model is also tested on a public drug data set,and achieved classification accuracy of 96.97%without preprocessing algorithm,which is 34.85%,28.28%,5.05%,and 2.73%higher than PLS DA,SVM,SAE,and CNN,respectively.The research shows that the SpectraTr model performs exceptionally well in spectral analysis and is expected to be a novel deep calibration model after Autoencoder networks(AEs)and CNN. 展开更多
关键词 Near-infrared spectroscopy analysis drug supervision transformer structure deep learning CHEMOMETRICS
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Formation of the structure-Ⅱgas hydrate from low-concentration propane mixed with methane
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作者 Sanya Du Xiaomin Han +8 位作者 Wenjiu Cai Jinlong Zhu Xiaobai Ma Songbai Han Dongfeng Chen Yusheng Zhao Hui Li Hailong Lu Xiaohui Yu 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2023年第6期306-314,共9页
It has been recognized that a small amount of propane mixed with methane can change greatly in not only the thermodynamics but also the structural properties of gas hydrate.However,its mechanism is still not well unde... It has been recognized that a small amount of propane mixed with methane can change greatly in not only the thermodynamics but also the structural properties of gas hydrate.However,its mechanism is still not well understood yet.In this research,structure-Ⅱ(sⅡ)hydrate is synthesized using a methanepropane gas mixture with an initial mole ratio of 99:1,and it is found that large(5~(12)6~4)cages are cooccupied by multiple gases based on the rigid structure analysis of neutron diffraction data.The first principles calculation and molecular dynamics simulation are conducted to uncover the molecular mechanism for sⅡmethane-propane hydrate formation,revealing that the presence of propane inhibits the formation of structure-Ⅰ(sⅠ)hydrate but promotes sⅡhydrate formation.The results help to understand the accumulation mechanism of natural gas hydrate and benefit to optimize the condition for gas storage and transportation in hydrate form. 展开更多
关键词 Multiple guest molecules CLATHRATES Neutron powder diffraction Structural transformation Molecular mechanism
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Spatiotemporal transformable nano-assembly for on-demand drug delivery to enhance anti-tumor immunotherapy
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作者 Chenglin Liang Ge Zhang +5 位作者 Linlin Guo Xinyi Ding Heng Yang Hongling Zhang Zhenzhong Zhang Lin Hou 《Asian Journal of Pharmaceutical Sciences》 SCIE CAS 2024年第1期103-118,共16页
Induction of tumor cell senescence has become a promising strategy for anti-tumor immunotherapy,but fibrotic matrix severely blocks senescence inducers penetration and immune cells infiltration.Herein,we designed a ca... Induction of tumor cell senescence has become a promising strategy for anti-tumor immunotherapy,but fibrotic matrix severely blocks senescence inducers penetration and immune cells infiltration.Herein,we designed a cancer-associated fibroblasts(CAFs)triggered structure-transformable nano-assembly(HSD-P@V),which can directionally deliver valsartan(Val,CAFs regulator)and doxorubicin(DOX,senescence inducer)to the specific targets.In detail,DOX is conjugated with hyaluronic acid(HA)via diselenide bonds(Se-Se)to form HSD micelles,while CAFs-sensitive peptide is grafted onto the HSD to form a hydrophilic polymer,which is coated on Val nanocrystals(VNs)surface for improving the stability and achieving responsive release.Once arriving at tumor microenvironment and touching CAFs,HSD-P@V disintegrates into VNs and HSD micelles due to sensitive peptide detachment.VNs can degrade the extracellularmatrix,leading to the enhanced penetration of HSD.HSD targets tumor cells,releases DOX to induce senescence,and recruits effector immune cells.Furthermore,senescent cells are cleared by the recruited immune cells to finish the integrated anti-tumor therapy.In vitro and in vivo results show that the nanoassembly remarkably inhibits tumor growth as well as lungmetastasis,and extends tumorbearing mice survival.This work provides a promising paradigm of programmed delivering multi-site nanomedicine for cancer immunotherapy. 展开更多
关键词 Cells senescence Tumor stroma structure transformable Programmed delivery Anti-tumor immunotherapy
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Nickel Sulfide Modified NiCu Nanoalloy with Excellent Oxygen Evolution Reaction Properties Prepared through Electrospinning and Heat Treatment
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作者 李涛 凌帅 +1 位作者 ZHONG Shujie LOU Qiongyue 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS CSCD 2024年第2期320-326,共7页
Ni^(2+)/Cu^(2+)/SO_(4)^(2-)/polyvinyl alcohol precursor fibers with uniform diameters were prepared through electrospinning.Nickel-based composite nanoalloys containing Ni,Cu,and S were prepared through heat treatment... Ni^(2+)/Cu^(2+)/SO_(4)^(2-)/polyvinyl alcohol precursor fibers with uniform diameters were prepared through electrospinning.Nickel-based composite nanoalloys containing Ni,Cu,and S were prepared through heat treatment in an Ar atmosphere.The experimental results show that the main components of the prepared nanoalloys are NiCu,Ni_(3)S_(2),Ni,and C.The nanoalloys exhibit fine grain sizes about 200-500 nm,which can increase with increasing heat treatment temperature.Electrochemical test results show that the nickel sulfidemodified NiCu nanoalloy composites exhibit excellent oxygen evolution reaction properties,and the oxygen evolution reaction properties gradually improve with the increasing heat treatment temperature.The sample prepared at 1 000℃ for 40 min show a low overpotential of 423 mV and a small Tafel slope of 134 mV·dec^(-1) at a current density of 10 mA·cm^(-2). 展开更多
关键词 NICU NANOALLOY Ni_(3)S_(2) structure transformation oxygen evolution reaction
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Synthesis and Structure Transformation of Orthorhombic LiMnO2 Cathode Materials by Sol-gel Method 被引量:1
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作者 ShixiZHAO HanxingLIU +1 位作者 QiangLI ShixiOUYANG 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2004年第1期46-48,共3页
Orthorhombic LiMnO2 cathode materials were synthesized successfully at lower temperature by sol-gel method. When LiMnO2 precursor prepared by sol-gel method was fired in air, the product was a mixture of spinel struct... Orthorhombic LiMnO2 cathode materials were synthesized successfully at lower temperature by sol-gel method. When LiMnO2 precursor prepared by sol-gel method was fired in air, the product was a mixture of spinel structure LiMn2O4 and rock-salt structure Li2MnO3, whereas in argon single-phase orthorhombic LiMnO2 could obtain at the range of 750℃ to 920℃. The substitution of Mn by Zn2+ or Co3+ in LiMnO2 led to the structure of LiMnO2 transiting to Qα-LiFeO2. The results of electrochemical cycles indicated that the discharged capacity of orthorhombic-LiMnO2 was smaller at the initial stages, then gradually increased with the increasing of cycle number, finally the capacity stabilized to certain value after about 10th cycles. This phenomenon reveals that there is an activation process for orthorhombic LiMnO2 cathode materials during electrochemical cycles, which is a phase transition process from orthorhombic LiMnO2 to tetragonal spinel Li2Mn2O4. The capacity of orthorhombic LiMnO2 synthesized at lower temperature is larger than that synthesized at high temperature. 展开更多
关键词 Orthorhombic LiMnO2 SYNTHESIS structure transformation Sol-gel method
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Effectiveness of Land Use Structure Evolution to Industrial Structure Transformation 被引量:2
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作者 ZHOU Xian-peng ZHAI Wen-xia KE Xin-li 《Asian Agricultural Research》 2012年第4期50-51,55,共3页
Scarcity of land resources and transformation of industrial structure is a pair of contradictory elements.We derive the characteristics of land use structure and industrial structure transformation in Xining City usin... Scarcity of land resources and transformation of industrial structure is a pair of contradictory elements.We derive the characteristics of land use structure and industrial structure transformation in Xining City using Transformation Coefficient(TC):first,in the period 1999-2000,the land use structure coefficient(θ1) declined by 79.55%,but the overall evolution trend is gentle;second,the transformation coefficient of industrial structure(θ2) tended to decline ceaselessly on the whole,a decrease of 36.09%(overall,the transformation coefficient of industrial structure is slightly greater than the land use structure coefficient);third,the inter-annual variation of the two experienced ups and downs(in the period 1999-2007,the inter-annual variation was great and in the period 2008-2010,the inter-annual variation tended to be gentle).On the basis of autocorrelation and co-integration model,we draw the following conclusions through analysis:first,the land use structure in Xining City plays a role in promoting industrial structure transformation;second,there is a long-term equilibrium relationship between the two.Finally,relevant policy recommendations are put forward for the industrial development in Xining City. 展开更多
关键词 Land use structure Industrial structure transformation Transformation Coefficient Xining City
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Disclosing the active integration structure and robustness of a pseudo-tri-component electrocatalyst toward alkaline hydrogen evolution
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作者 Hong-Hong Zou Wan-Qing Li +7 位作者 Cong-Hu Song Li-Ming Cao Xue-Feng Zhang Xuan-Yi Zhu Zi-Yi Du Jia Zhang Sheng-Liang Zhong Chun-Ting He 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2022年第9期210-216,I0007,共8页
Designing multicomponent integration catalysts(MICs)has been a promising strategy for improving electrocatalytic hydrogen evolution reaction(HER)due to the highly active interfaces as well as electronic synergy.Nevert... Designing multicomponent integration catalysts(MICs)has been a promising strategy for improving electrocatalytic hydrogen evolution reaction(HER)due to the highly active interfaces as well as electronic synergy.Nevertheless,many fundamental questions such as their actual active species and the influence on long-term stability remain to be answered.Herein,we present the structural evolution from a pseudotri-component electrocatalyst of nitrogen-doped carbon supported nickel/vanadium nitride/vanadium oxide(Ni-VN-V_(2)O_(3)/NC)nanorods to the heterostructural nickel/vanadium nitride(Ni-VN/NC)nanosheets during chemical or electrochemical processes.The self-reconstructed Ni-VN/NC exhibits a robust stability under alkaline conditions,while maintaining initial efficient HER activity with a low overpotential of 76 mV at the current density of 10 mA cm^(-2).Theoretical calculations and quasi-in-situ spectroscopic technology unveil the redistribution of electrons on the synergistic active interface,which synchronously optimizes the affinities for hydrogen,hydroxide,and water molecules,thereby remarkably accelerating the HER kinetics by reducing the barrier of Volmer step. 展开更多
关键词 Hydrogen evolution reaction Multicomponent integration catalysts Structural transformation ELECTROCATALYSIS Density functional theory
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Impact of high dose Kr^+ ion irradiation on the corrosion behavior and microstructure of Zircaloy-4
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作者 QianWan XindeBai XiaoyangLiu 《Journal of University of Science and Technology Beijing》 CSCD 2005年第2期178-181,共4页
In order to investigate the ion irradiation effect on the corrosion behavior and microstructure of Zircaloy-4, the Zircaloy-4 film were prepared by electron beam deposition on the Zircaloy-4 specimen surface and irra... In order to investigate the ion irradiation effect on the corrosion behavior and microstructure of Zircaloy-4, the Zircaloy-4 film were prepared by electron beam deposition on the Zircaloy-4 specimen surface and irradiated by Kr ions using an accelerator at an energy of 300 keV with the dose from 1×1015 to 3×1016ions/cm2. The post-irradiation corrosion tests were conducted to rank the corrosion resistance of the resulting specimens by potentiodynamic polarization curve measurements in a 0.5 mol/L H2SO4 water so- lution at room temperature. Transmission electron microscopy (TEM) was employed to examine the microstructural change in the surface. The potentiodynamic tests show that with the irradiation dose increasing, the passive current density, closely related to the surface corrosion resistance, decreases firstly and increases subsequently. The mechanism of the corrosion behavior transformation is due to the amorphous phase formation firstly and the amorphous phase destruction and the polycrystalline structure formation in the irradiated surface subsequently. 展开更多
关键词 ZIRCALOY-4 irradiation damage corrosion resistance structure transformation
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Hamiltonian structure, Darboux transformation for a soliton hierarchy associated with Lie algebra so(4, C)
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作者 王新赠 董焕河 《Chinese Physics B》 SCIE EI CAS CSCD 2015年第8期130-136,共7页
In this paper, we first introduce a Lie algebra of the special orthogonal group, g = so(4, C), whose elements are 4 × 4trace-free, skew-symmetric complex matrices. As its application, we obtain a new soliton hier... In this paper, we first introduce a Lie algebra of the special orthogonal group, g = so(4, C), whose elements are 4 × 4trace-free, skew-symmetric complex matrices. As its application, we obtain a new soliton hierarchy which is reduced to AKNS hierarchy and present its bi-Hamiltonian structure and Liouville integrability. Furthermore, for one of the equations in the resulting hierarchy, we construct a Darboux matrix T depending on the spectral parameter λ. 展开更多
关键词 zero curvature equation recursion operator Hamiltonian structure Darboux transformation
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Coacervate Structures of CdI_2 Thin Film Grown during Phase Transformation
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作者 Xiaoyan YE and Lili CAO(Dept. of Chemistry, Tsinghua University, Beijing 100084, China)Jizhong ZHANG and Hengde LI(Dept. of Materials Scieuce & Engineering, Tsinghua University, Beijing 100084, China) 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 1997年第4期296-298,共3页
The microstructure of CdI2 thin film grown during vapor-phase deposition was investigated by scanning electron microscopy (SEM). The thin film deposited on Si crystal consists of numerous sunflower-like aggregates. Th... The microstructure of CdI2 thin film grown during vapor-phase deposition was investigated by scanning electron microscopy (SEM). The thin film deposited on Si crystal consists of numerous sunflower-like aggregates. These aggregates display well self-assembly characteristics. The size of Sunflower-like aggregates is between 12 and 44 μm. Each sunflower-like aggregate is surrounded with many adjacent wings-'petals'. The structure of central region of the 'sunflower' is obviously difFerent from that of the 'petal'. Electron spectroscopy for chemical analysis (ESCA) was employed in determining the chemical valence of the thin film. Self-organization efFect is used to explain the coring growth process of CdI2 thin film 展开更多
关键词 Thin Coacervate structures of CdI2 Thin Film Grown during Phase Transformation
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Simple Model of Transformation of a Crystal Structures
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作者 B. I. Lev 《Journal of Modern Physics》 2016年第16期2366-2373,共8页
A simple model of the closely packed structure for system of hard-sphere particles interacting via the long-range Newtonian type attraction is suggested. Based on density functional theory, the exact equation of ... A simple model of the closely packed structure for system of hard-sphere particles interacting via the long-range Newtonian type attraction is suggested. Based on density functional theory, the exact equation of state is obtained and the mutual transformations of the crystal structures in such systems are studied. The description takes into account the fact impossibility of hard-sphere particles which have the same spatial occupation place. 展开更多
关键词 Density Functional Theory Transformation of structures Close-Packing structure
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Impact of Two-Way FDI on the Industrial Structure in Shandong Province Under the Background of “New and Old Kinetic Energy Conversion”
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作者 Zhiqing Xia Ge Song Zahid Hussain 《Proceedings of Business and Economic Studies》 2022年第5期153-157,共5页
This paper uses the panel data of 17 cities in Shandong Province from 2003 to 2018 to construct a panel model to empirically study the impact of foreign direct investment(FDI)on the industrial structure.The results sh... This paper uses the panel data of 17 cities in Shandong Province from 2003 to 2018 to construct a panel model to empirically study the impact of foreign direct investment(FDI)on the industrial structure.The results show that two-way investment,financial industry development,and policy variables have significant roles in promoting the advancement of the industrial structure in the province.In the future implementation of the“Going Global”strategy in Shandong Province,the cooperation between two-way investment and the financial industry should be strengthened,the level of regional financial development should be improved,and the impact of two-way investment on the optimization and upgrading of the industrial structure should be reinforced. 展开更多
关键词 New and old kinetic energy conversion Foreign direct investment Industrial structure transformation
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Gender and rural transformation:A systematic literature review 被引量:1
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作者 Maria Fay ROLA-RUBZEN Hue T.VUONG +4 位作者 Claire DOLL Curtis ROLLINS Jon Marx SARMIENTO Mohammad Jahangir ALAM Ismat Ara BEGUM 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2023年第12期3624-3637,共14页
Rural transformation can improve poverty reduction,living standards,and health outcomes in developing countries.However,impacts associated with rural transformation vary by region,household,and individual trait(includ... Rural transformation can improve poverty reduction,living standards,and health outcomes in developing countries.However,impacts associated with rural transformation vary by region,household,and individual trait(including gender).While research on rural transformation has been increasing over the last decade,there has been no comprehensive review conducted on the relationships between gender and rural transformation.Here,we conduct a systematic literature review to investigate the impacts of rural transformation on gender and the influence of gender inclusiveness on rural transformation.We reviewed 82 studies from 1960-2021 that explore the relationships between rural transformation and gender.We then developed a framework that captures incidences and flow directions between indicators.Results show that most studies examined the impacts of rural transformation on women and between gender indicators.Few investigated the role of women and the influence of gender inclusiveness on rural transformation.Overall,studies showed that rural transformation typically leads to positive outcomes for women regarding employment,income,and empowerment.However,negative impacts on women’s control over income,stability of new income sources,and access to healthy food are also common.Tailoring future development policies and programs to explicitly account for gender inclusiveness can lead to more successful rural transformation. 展开更多
关键词 GENDER rural transformation structural transformation women’s empowerment
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Topotactically constructed nickel-iron(oxy)hydroxide with abundant in-situ produced high-valent iron species for efficient water oxidation 被引量:2
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作者 Zhichong Kuang Song Liu +10 位作者 Xuning Li Meng Wang Xinyi Ren Jie Ding Rile Ge Wenhui Zhou Alexandre IRykov Moulay TSougrati Pierre-Emmanuel Lippens Yanqiang Huang Junhu Wang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2021年第6期212-218,I0006,共8页
The low efficiency of oxygen evolution reaction(OER) is regarded as one of the major roadblocks for metal-air batteries and water electrolysis.Herein,a high-performance OER catalyst of NiFe_(0.2)(oxy)hydroxide(NiFe_(0... The low efficiency of oxygen evolution reaction(OER) is regarded as one of the major roadblocks for metal-air batteries and water electrolysis.Herein,a high-performance OER catalyst of NiFe_(0.2)(oxy)hydroxide(NiFe_(0.2)-O_(x)H_(y)) was developed through topotactic transformation of a Prussian blue analogue in an alkaline solution,which exhibits a low overpotential of only 263 mV to reach a current density of 10 mA cm^(-2) and a small Tafel slope of 35 mV dec-1.Ex-situ/operando Raman spectroscopy results indicated that the phase structure of NiFe_(0.2)-O_(x)H_(y) was irreversibly transformed from the type of α-Ni(OH)_(2) to γ-NiOOH with applying an anodic potential,while ex-situ/operando 57Fe Mossbauer spectroscopic studies evidenced the in-situ production of abundant high-valent iron species under OER conditions,which effectively promoted the OER catalysis.Our work elucidates that the amount of high-valent iron species in-situ produced in the NiFe(oxy)hydroxide has a positive correlation with its water oxidation reaction performance,which further deepens the understanding of the mechanism of NiFe-based electrocatalysts. 展开更多
关键词 Oxygen evolution reaction Topotactic construction Structural transformation Operando Mssbauer spectroscopy High-valent iron ions
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Tuning electrochemical transformation process of zeolitic imidazolate framework for efficient water oxidation activity 被引量:1
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作者 Zhanwu Lei Xu Jin +4 位作者 Jianming Li Yang Liu Jian Liu Shuhong Jiao Ruiguo Cao 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2022年第2期505-513,共9页
Metal-organic frameworks(MOFs)have been widely studied as efficient electrocatalysts for water oxidation due to their tunable structure and easy preparation.However,the rational design of MOFs-based electrocatalysts a... Metal-organic frameworks(MOFs)have been widely studied as efficient electrocatalysts for water oxidation due to their tunable structure and easy preparation.However,the rational design of MOFs-based electrocatalysts and fundamental understanding of their structural evolution during oxygen evolution reaction(OER)remain critical challenges.Here,we report a facile approach to tune the structural transformation process of the Co-based zeolitic imidazolate framework(ZIF)during the OER process by using water molecules as a vacancy promoter.The modified ZIF catalyst accelerates the structural transformation from MOF precursor to electrochemical active species and simultaneously enhances the vacancy density during the electrochemical activation process.The optimized electrocatalyst exhibits an extremely low overpotential 175 mV to deliver 10 mA cm^(-2) and superior durability(100 h)at 100 mA cm^(-2).The comprehensive characterization results reveal the structural transformation from the initial tetrahedral Co sites to cobalt oxyhydroxide(CoOOH)and the formation process of oxygen vacancies(CoOOH-Vo)at a high anodic potential.These findings represent a promising way to achieve highly active MOF-based electrocatalysts for water oxidation. 展开更多
关键词 Metal-organic framework Structural transformation ELECTROCATALYST Water splitting
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Hcp-icosahedron structural transformation induced by the change in Ag concentration during the freezing of (CoAg)_(561) clusters 被引量:1
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作者 肖绪洋 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第4期424-427,共4页
The synergy effect of alloy elements in bimetallic clusters can be used to tune the chemical and physical properties. Research on the influences of alloy concentration and distribution on the frozen structure of bimet... The synergy effect of alloy elements in bimetallic clusters can be used to tune the chemical and physical properties. Research on the influences of alloy concentration and distribution on the frozen structure of bimetallic clusters plays a key rolc in exploring new structural materials. In this paper, we study the influence of Ag concentration on the frozen structure of the (AgCo)561 cluster by using molecular dynamics simulation with a general embedded atom method. The results indicate that tt^e structure and chemical ordering of the (AgCo)561 cluster are strongly related to Ag concentration. Hcp-icosahedron structural transformation in the frozen (CoAg)561 cluster can be induced by changing Ag concentration. The chemical ordering also transforms to Janus-like Co Ag from core-shell Co-Ag. 展开更多
关键词 bimetallic cluster freeze molecular dynamics structural transformation
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A Universal Atomic Substitution Conversion Strategy Towards Synthesis of Large‑Size Ultrathin Nonlayered Two‑Dimensional Materials 被引量:1
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作者 Mei Zhao Sijie Yang +10 位作者 Kenan Zhang Lijie Zhang Ping Chen Sanjun Yang Yang Zhao Xiang Ding Xiaotao Zu Yuan Li Yinghe Zhao Liang Qiao Tianyou Zhai 《Nano-Micro Letters》 SCIE EI CAS CSCD 2021年第11期79-91,共13页
Nonlayered two-dimensional(2D)materials have attracted increasing attention,due to novel physical properties,unique surface structure,and high compatibility with microfabrication technique.However,owing to the inheren... Nonlayered two-dimensional(2D)materials have attracted increasing attention,due to novel physical properties,unique surface structure,and high compatibility with microfabrication technique.However,owing to the inherent strong covalent bonds,the direct synthesis of 2D planar structure from nonlayered materials,especially for the realization of large-size ultrathin 2D nonlayered materials,is still a huge challenge.Here,a general atomic substitution conversion strategy is proposed to synthesize large-size,ultrathin nonlayered 2D materials.Taking nonlayered CdS as a typical example,large-size ultrathin nonlayered CdS single-crystalline flakes are successfully achieved via a facile low-temperature chemical sulfurization method,where pre-grown layered CdI2 flakes are employed as the precursor via a simple hot plate assisted vertical vapor deposition method.The size and thickness of CdS flakes can be controlled by the CdI2 precursor.The growth mechanism is ascribed to the chemical substitution reaction from I to S atoms between CdI2 and CdS,which has been evidenced by experiments and theoretical calculations.The atomic substitution conversion strategy demonstrates that the existing 2D layered materials can serve as the precursor for difficult-to-synthesize nonlayered 2D materials,providing a bridge between layered and nonlayered materials,meanwhile realizing the fabrication of large-size ultrathin nonlayered 2D materials. 展开更多
关键词 Nonlayered 2D materials Large-size ultrathin CdS flakes Atomic substitution conversion Layered-nonlayered structural transformation
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Evidence of polymorphic transformations of Sn under high pressure
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作者 敬秋民 曹玉红 +8 位作者 张毅 李守瑞 何强 侯琪玥 刘盛刚 柳雷 毕延 耿华运 吴强 《Chinese Physics B》 SCIE EI CAS CSCD 2016年第12期202-206,共5页
The high-pressure polymorphs and structural transformation of Sn were experimentally investigated using angle- dispersive synchrotron x-ray diffraction up to 108.9 GPa. The results show that at least at 12.8 GPa β-Sn... The high-pressure polymorphs and structural transformation of Sn were experimentally investigated using angle- dispersive synchrotron x-ray diffraction up to 108.9 GPa. The results show that at least at 12.8 GPa β-Sn→bct structure transformation was completed and no two-phase coexistence was found. By using a long-wavelength x-ray, we resolved the diffraction peaks splitting and discovered the formation of a new distorted orthorhombic structure bco from the bct structure at 31.8 GPa. The variation of the lattice parameters and their ratios with pressure further validate the observation of the bco polymorph. The bcc structure appears at 40.9 GPa and coexists with the bco phase throughout a wide pressure range of 40.9 GPa-73.1 GPa. Above 73.1 GPa, only the bcc polymorph is observed, The systematically experimental investigation confirms the phase transition sequence of Sn asβ-Sn→bct→bco→bco + bcc→bcc upon compression to 108.9 GPa at room temperature. 展开更多
关键词 high-pressure POLYMORPH structural transformation SN
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First principles study of post-boron carbide phases with icosahedra broken
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作者 陈明伟 梁钊 +3 位作者 刘美玲 Uppalapati Pramod Kumar 刘超 梁彤祥 《Chinese Physics B》 SCIE EI CAS CSCD 2020年第10期214-221,共8页
Boron carbide (B4C) is a rhombic structure composed of icosahedra and atomic chains, which has an important application in armored materials. The application of B4C under super high pressure without failure is a hot s... Boron carbide (B4C) is a rhombic structure composed of icosahedra and atomic chains, which has an important application in armored materials. The application of B4C under super high pressure without failure is a hot spot of research. Previous studies have unmasked the essential cause of B4C failure, i.e., its structure will change subjected to impact, especially under the non-hydrostatic pressure and shear stress. However, the change of structure has not been clearly understood nor accurately determined. Here in this paper, we propose several B4C polymorphs including B4C high pressure phases with non-icosahedra, which are denoted as post-B4C and their structures are formed due to icosahedra broken and may be obtained through high pressure and high temperature (HPHT). The research of their physical properties indicates that these B4C polymorphs have outstanding mechanical and electrical properties. For instance, aP10, mC10, mP20, and oP10-B4C are conductive superhard materials. We hope that our research will enrich the cognition of high pressure structural deformation of B4C and broaden the application scope of B4C. 展开更多
关键词 boron carbide structural transformation icosahedra broken physical properties first principles
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Structural transformation of metal–organic framework with constructed tetravalent nickel sites for efficient water oxidation
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作者 Weijian Wu Zhen Gao +6 位作者 Qun Li Zhiya Wang Shiyin Liu Hongbo Wu Yuanchun Zhao Yalong Jiao Xiaojia Zhao 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2022年第11期404-411,I0011,共9页
A mixture of Ni and Fe oxides is among the most commonly active catalysts for the oxygen evolution reaction(OER)during the water oxidation process.In particular,Ni oxide incorporated with even a small amount of Fe lea... A mixture of Ni and Fe oxides is among the most commonly active catalysts for the oxygen evolution reaction(OER)during the water oxidation process.In particular,Ni oxide incorporated with even a small amount of Fe leads to substantively enhanced OER activity.However,the critical role of Fe species during the electrocatalytic process is still under evaluation.Herein,we report nickel(oxy)hydroxide incorporated with Fe through the surface reconstruction of a bimetallic metal-organic framework(NiFe-MOF)during the water oxidation process.The spectroscopic investigations with theoretical calculations reveal the critical role of Fe in promoting the formation of highly oxidized Ni^(4+),which directly correlates with an enhanced OER activity.Both the geometric and electronic structu res of the as-reconstructed Ni_(1-x)Fe_(x)OOH electrocatalysts can be delicately tuned by the Ni-Fe ratio of the bimetallic NiFe-MOF,further affecting the catalytic activity.As a result,the Ni_(1-x)Fe_(x)OOH derived from Ni_(0.9)Fe_(0.1)-MOF delivers low overpotentials of 260 mV at 10 mA cm^(-2)and 400 mV at 300 mA cm^(-2). 展开更多
关键词 Structural transformation Bimetallic metal-organic framework Oxygen evolution reaction In-situ Raman spectroscopy High-valence metal sites
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